Data recording medium, data recording method and apparatus, data playback method and apparatus, and data determination method

ABSTRACT

A recording medium includes an area in which data encoded with an error correction code is recorded. In the recording medium, data which contains an error uncorrectable with the error correction code, and data which does not contain an error uncorrectable with the error correction code are recorded in predetermined pattern.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a recording medium, a recordingmethod of a recording medium, a recording apparatus of a recordingmedium, a playback method of a recording medium, a playback apparatus ofa recording medium, and a data determination method. In particular, thepresent invention relates to a recording medium in which data encodedwith error correction coding is recorded, a recording method of therecording medium, a recording apparatus of the recording medium, aplayback method of the recording medium, a playback apparatus of therecording medium, and a data determination method for determining dataencoded with error correction coding.

[0003] 2. Description of the Related Art

[0004] Optical discs such as CDs (Compact Discs) having music datarecorded therein (hereinafter referred to as “CD-DA (Compact DiscDigital Audio)”) and CD-ROM (Compact Disc Read-Only Memory) discs arewidely accepted as data recording media because such discs are easy tohandle and inexpensive. Recently, CD-R (Compact Disc Recordable) discscapable of recording data or CD-RW (Compact Disc ReWritable) discscapable of rewriting data have been commercially available, and userscan easily record data in such optical discs. Optical discs complyingwith the CD standards, including CD-DA, CD-ROM, CD-R, and CD-RW discs,have become dominant in the field of data recording media. In recentyears, it has been accomplished to compress audio data in the format ofMP3 (MPEG1 Audio Layer-3) or ATRAC3 (Adaptive TRansform Acoustic Coding3) (trademark) and to record the compressed data in discs such asCD-ROM, CD-R, and CD-RW discs.

[0005] However, with the advent of CD-R or CD-RW discs, data recorded inCD-DA or CD-ROM discs has been able to be easily copied, and the demandsfor copyright protection have been increasingly required. Therefore, itis necessary to take some action for copyright protection of contentdata when the content data is recorded in a CD-DA or CD-ROM disc.

[0006] One method for protecting content data recorded in a CD-DA orCD-ROM disc is to encode the content data before the data is recorded inthe disc. The content data encoded before being recorded in a disccannot be decoded unless data concerning key for decoding the contentdata is obtained, so that the content data can be protected. Anothermethod is to add DRM (Digital Rights Management) data which indicatescopyright protection information of content data so as to establish aplayback and copy restriction system of the content data.

[0007] Initially, a system employing CD discs was a playback-onlyrecording medium, and is therefore difficult to achieve effectivecopyright protection. In particular, some existing CD-R or CD-RW driveshave a disc-copy function. Such drives enables data in one disc to becopied to another disc. The disc-copy function would allow for copyingof content data even if the content data is encoded or has DRM datarecorded therein.

[0008] In order to address illegal copying of content data by a disccopy, a method is required for determining whether data recorded in adisc is original data or copied data.

[0009] For example, one method for determining whether data recorded ina CD-ROM disc is original data or copied data utilizes thecharacteristics of CD-ROM data encoded with error correction coding.CD-ROM data is encoded with CIRC (cross-interleaved Reed-Solomon code)error correction coding, and is error corrected in order to increase theerror correction performance. In a known method, an error correctioncode, a sync pattern, a header, a scrambled signal, etc., are corruptedby intention in CD-ROM (CD-ROM mode 1) and, based on whether or not thecorrupted error correction code, sync pattern, header, scrambled signal,etc., are present, it is determined whether or not the disc is anoriginal disc.

[0010] However, some recent CD-R or CD-RW drives are able to generatethis type of error, and application software for making a disc copyusing such a method may be commercially available. Thus, this method maybe no longer useful for determining whether data recorded in a CD discis original data or copied data.

SUMMARY OF THE INVENTION

[0011] It is therefore an object of the present invention to provide arecording medium which solves the above-mentioned problem.

[0012] It is another object of the present invention to provide arecording method of a recording medium which solves the above-mentionedproblem.

[0013] It is a further object of the present invention to provide arecording apparatus of a recording medium which solves theabove-mentioned problem.

[0014] It is a still further object of the present invention to providea playback method of a recording medium which solves the above-mentionedproblem.

[0015] It is a yet further object of the present invention to provide aplayback apparatus of a recording medium which solves theabove-mentioned problem.

[0016] It is another object of the present invention to provide a datadetermination method which solves the above-mentioned problem.

[0017] According to the present invention, there is provided a recordingmedium including an area in which data encoded with an error correctioncode is recorded. In the recording medium, erroneous uncorrectable datawhich contains an uncorrectable error which cannot be corrected with theerror correction code, and erroneous correctable data which does notcontain an uncorrectable error which cannot be corrected with the errorcorrection code are recorded in predetermined pattern.

[0018] According to the present invention, there is provided a recordingmethod. The recording method includes the steps of recording dataencoded with an error correction code in a recording area of a recordingmedium; and recording erroneous uncorrectable data which contains anuncorrectable error which cannot be corrected with the error correctioncode and erroneous correctable data which does not contain anuncorrectable error which cannot be corrected with the error correctioncode in predetermined pattern at predetermined position of the recordingmedium.

[0019] According to the present invention, there is provided a recordingapparatus of a recording medium, including a recording unit, an errorcorrection coding unit, a modulation unit, and a data generation unit.The recording unit records data in the recording medium. The errorcorrection coding unit encodes input data with a first error correctioncode. The modulation unit modulates the output data of the errorcorrection coding unit, and outputs the modulated data to the recordingunit. The data generation unit generates data which can be decoded withboth the first error correction code and a second error correction codedifferent from the first error correction code, and supplies thegenerated data to the error correction coding unit.

[0020] According to the present invention, there is provided a playbackapparatus of a recording medium. The playback apparatus includes a head,a demodulation unit, an error correction unit, and a determination unit.The head reads data recorded in the recording medium. The demodulationunit demodulates the output signal of the head. The error correctionunit performs error correction on the output data of the demodulationunit. The determination unit determines the recording medium based onwhether or not the result of the error correction performed by the errorcorrection unit is a predetermined result.

[0021] According to the present invention, there is provided a playbackmethod of a recording medium. The playback method includes the steps ofreading data recorded in the recording medium, demodulating the readdata, performing error correction on the demodulated data, anddetermining the recording medium based on whether or not the result ofthe error correction is a predetermined result.

[0022] According to the present invention, there is provided a datadetermination method. The data determination method includes the stepsof performing error correction on transmitted data, and determiningwhether or not the transmitted data is original data based on whether ornot the result of the error correction is a predetermined result.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1 is a plan view of an optical disc according to the presentinvention;

[0024]FIG. 2 is a schematic diagram of the optical disc of the presentinvention;

[0025]FIG. 3 is a block diagram of the optical disc of the presentinvention;

[0026]FIG. 4 is a schematic diagram of the optical disc of the presentinvention;

[0027]FIG. 5 is a schematic block diagram for illustrating the recordingformat of the optical disc of the present invention;

[0028]FIG. 6 is a schematic diagram for illustrating the recordingformat of the optical disc of the present invention;

[0029]FIG. 7 is a schematic block diagram for illustrating the recordingformat of the optical disc of the present invention;

[0030]FIG. 8 is a schematic diagram for illustrating the recordingformat of the optical disc of the present invention;

[0031]FIG. 9 is a schematic diagram for illustrating the interleavingprocess in CIRC4;

[0032]FIG. 10 is a schematic diagram for illustrating the interleavingprocess in CIRC7;

[0033]FIG. 11 is schematic diagram for illustrating data which can bedecoded with both the CIRC4 and CIRC7 error correction codes;

[0034]FIG. 12 is a schematic diagram of the optical disc of the presentinvention;

[0035]FIG. 13 is a block diagram for illustrating a disc copy accordingto the present invention;

[0036]FIGS. 14A and 14B are schematic diagrams of the optical disc ofthe present invention;

[0037]FIG. 15 is a block diagram of an optical disc recording apparatusaccording to the present invention;

[0038]FIG. 16 is a block diagram of an optical disc playback apparatusaccording to the present invention;

[0039]FIG. 17 is a flowchart for illustrating a process for determiningwhether or not a disc is original;

[0040]FIG. 18 is a schematic diagram of another structure of the opticaldisc according to the present invention; and

[0041]FIG. 19 is a schematic diagram of a modification of the opticaldisc of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] The present invention is described below with reference to thedrawings taken in conjunction with an embodiment thereof. In thisembodiment, a novel optical disc is used as a recording medium. Theoptical disc of the present invention complies with substantially thesame physical standards, such as size, as that of a CD-DA disc, and anexisting disk drive can be used to optically read information on thedisc.

[0043] The optical disc of the present invention contains encodedcontent data. The encoded content data may be the encoded version ofcontent data such as audio or image data in CD-ROM format or in CD-DAformat. The content data may be encoded using an encryption techniquesuch as DES (Data Encryption Standard). The content data is furthercompressed using ATRAC3 (Adaptive TRansform Acoustic Coding 3)(trademark), MP3 (MPEG1 Audio Layer-3 ), AAC (MPEG2 Advanced AudioCoding), TwinVQ (Transform-domain Weighted Interleave VectorQuantization), or the like, as required.

[0044] Referring to FIG. 1, an optical disc 1 of the present inventionhas a diameter of 120 mm, and a hole 2 is formed at the center of theoptical disc 1. The optical disc 1 may be a disc with a diameter of 80mm known as a “CD single”.

[0045] The optical disc 1 may be a playback-only disc, a recordabledisc, or a rewritable disc.

[0046] If the optical disc 1 is a playback-only disc, the recordinglayer of the optical disc 1 is made of aluminum. Information is recordedin pattern of physical pits on the playback-only optical disc 1, and adisc is typically manufactured using a stamper.

[0047] If the optical disc 1 is a recordable disc, the recording layerof the optical disc 1 is made of organic dye such as phthalocyanine orcyanine dye. The recording layer made of such organic dye is heated by alaser during the recording process. Then, the organic dye is melted.

[0048] If the optical disc 1 is a rewritable disc, the recording layerof the optical disc 1 is made of a phase change material. Examples ofthe phase change material include Ag—In—Sb—Te(silver-indium-antimony-tellurium) alloy. The phase change material hasboth a crystal phase and an amorphous phase. During the recordingprocess, the phase change recording layer is heated to the melting pointor higher, and is then cooled rapidly to an amorphous state. During theerasing process, the phase change recording layer is heated nearly tothe crystallization temperature, and is then cooled gradually to acrystalline state.

[0049] As shown in FIGS. 1 and 2, the optical disc 1 is formed of afirst lead-in area LI1 at the innermost circumference thereof, a firstprogram area PA1 surrounding the first lead-in area LI1, and a firstlead-out area LO1 surrounding the first program area PA1. The firstprogram area PA1 contains audio data in similar recording format toCD-DA format. Since the data in the first program area PA1 is in similarrecording format to that of CD-DA discs, and is not encoded, the datacan be played back using a general-purpose music player.

[0050] The optical disc 1 is further formed of a second lead-in area LI2surrounding the first lead-out area LO1, a second program area PA2surrounding the second lead-in area LI2, and a second lead-out area LO2surrounding the second program area PA2. The second program area PA2contains as content data audio data which is compressed using, forexample, ATRAC3, as discussed above, and which is encoded.

[0051] The second program area PA2 is divided into two subareas AR1 andAR2. The subarea AR1 has data recorded therein which is encoded witherror correction coding similar to that in typical CD-DA or CD-ROM discs(hereinafter referred to as a “CIRC4”). The subarea AR2 has datarecorded therein which is encoded with error correction coding whichwill be employed in double density CD discs (hereinafter referred to as“CIRC7”). The data recorded in the subarea AR2 includes data patternwhich can also be decoded with the CIRC4 error correction code. TheCIRC7 scheme is described in Japanese Laid-Open Patent No. 9-91882.

[0052] The data recorded in the subarea AR1 of the second program areaPA2 is encoded with a CIRC4 error correction code in order to providecompatibility with CD-DA discs.

[0053] In the optical disc 1 of the present invention, as discussedabove, the second program area PA2 is divided into two subareas AR1andAR2containing data encoded with different error correction codes. Thedata recorded in the subarea AR1is encoded with a CIRC4 error correctioncode while the data recorded in the subarea AR2is encoded with a CIRC7error correction code. The subarea AR2also contains data pattern whichcan be decoded with both the CIRC7 and CIRC4 error correction codes.

[0054] An error correction code is applied for detection or correctionof a burst error or random error. In the optical disc 1 of the presentinvention, however, as described below, the characteristics of the CIRC4and CIRC7 error correction codes can be used to determine whether thedata recorded in the optical disc 1 is original data or copied databased on the error corrected data in the subarea AR2.

[0055] A description is now given of the CIRC4 error correction code andthe CIRC7 error correction code.

[0056] CDs employ CIRC error correction coding in which data is encodedwith dual error correction coding in a C1 (vertical) sequence and in aC2 (diagonal) sequence. The thus error correction coded data issubjected to eight-to-fourteen (EFM) modulation per frame, and isrecorded.

[0057]FIG. 3 shows one frame of the CD data structure before the EFMmodulation.

[0058] As shown in FIG. 3, when audio data is sampled in units of 16bits, one frame is formed of data bits of 24 symbols (one symbol is inthe form of 8 bits obtained by halving 16 bits) corresponding to sixsamples for the left (L) and six samples for the right (R), P parity offour symbols, Q parity of four symbols, and a subcode of one symbol.One-frame data recorded on the disc is EFM modulated to convert from8-bit data to 14-bit data, and a DC suppression bit and a frame sync areadded to the data.

[0059] Therefore, one-frame data recorded on the disc is formed of:

[0060] 24-channel-bit frame sync;

[0061] 336-channel-bit data bits (given by 14×24=336);

[0062] 14-channel-bit subcode;

[0063] 112-channel-bit parity (given by 14×8=112); and

[0064] 102-channel-bit margin bits (given by 3×34=102).

[0065] The total of 588 channel bits construct one frame.

[0066] In one frame, the subcode (one symbol) includes eight channels Pto W each in the form of one bit. As shown in FIG. 4, one sector iscomposed of 98-frame data (the subcode spans 98 contiguous frames). Inthe subcode, the first two frames of 98 frames are designated by subcodeframe sync characters S₀ and S₁. When data is recorded in an opticaldisc such as CD-ROM, 98 frames (2,352 bytes) of a period of the subcodeconstruct one sector.

[0067]FIGS. 5 and 6 are block diagrams illustrating a CIRC encodingprocess. In the following description of CIRC encoding/decoding, audiodata is encoded, by way of example, for ease of understanding.

[0068] In an audio signal, 24 symbols (W12n,A; W12n,B; . . . W12n+11,A;and W12n+11,B) in which one word is divided into the upper eight bitsand the lower eight bits (the upper eight bits are designated by A andthe lower eight bits are designated by B) are supplied to a two-symboldelay/scrambling circuit 11. The two-symbol delay processing isperformed on the even-word data indicated by L6n, R6n, L6n+2, R6n+2,etc., so that, if an error occurs in all the C2 sequence, the error maybe interpolated in a C2 encoder 12. The scrambling is performed in orderto obtain the maximum burst-error interpolation length.

[0069] The data output from the two-symbol delay/scrambling circuit 11is supplied to the C2 encoder 12. In the C2 encoder 12, the data isencoded with a (28, 24, 5) Reed-Solomon code over GF(2⁸) so as togenerate the Q parity of four symbols Q12n, Q12n+1, Q12n+2, and Q12n+3.

[0070] The output (28 symbols) of the C2 encoder 12 is supplied tointerleaving circuits 13. The interleaving circuits 13 provide delayamounts which vary with an equal difference, such as 0, D, 2D, etc., forthe symbols, where D indicates the unit delay amount, so as tointerleave the symbols.

[0071] The output of the interleaving circuits 13 is supplied to a C1encoder 14. A (32, 28, 5) Reed-Solomon code over GF(2⁸) is used as a C1code. The P parity of four symbols P12n, P12n+1, P12n+2, and P12n+3 aregenerated from the C1 encoder 14. The minimum distance of both the C1code and the C2 code is five. This enables two-symbol errors to becorrected, and enables four-symbol errors to be corrected by erasing (ifthe position of error symbols is known).

[0072] The 32 symbols from the C1 encoder 14 are supplied to aone-symbol delay circuit 15. The one-symbol delay circuit 15 allowsadjacent symbols to be spaced apart from each other, thus preventingoccurrence of a two-symbol error due to an error over the adjacentsymbols. The Q parity is inverted by an inverter in order to detect anerror even when all data and parities become zero.

[0073] The unit delay amount D of the interleaving circuit 13 in CIRC4is different from that in CIRC7. The interleaving circuits 13 enableburst errors to be dispersed.

[0074] Specifically, in CIRC4, the unit delay amount D is equal to fourframes, and adjacent symbols are located four frames apart. The CIRC4scheme in which D=4 frames is used in the present CD-DA standard. InCIRC4, the maximum delay amount is 27D (=108 frames), and the totalinterleave length is 109 frames.

[0075] In CIRC7, the unit delay amount D is equal to seven frames, andadjacent symbols are located seven frames apart. The CIRC7 scheme inwhich D=7 frames will be used in the double density CD standard. InCIRC7, the maximum delay amount is 27D (=189 frames), and the totalinterleave length is 190 frames.

[0076]FIGS. 7 and 8 are block diagrams illustrating a decoding process.The decoding process is performed in a reverse manner to theabove-described encoding process.

[0077] First, playback data from an EFM demodulation circuit is suppliedto a one-symbol delay circuit 21. The delay added by the one-symboldelay circuit 15 in the encoding system is cancelled by the one-symboldelay circuit 21.

[0078] The 32 symbols from the one-symbol delay circuit 21 are suppliedto a C1 decoder 22. The output data of the C1 decoder 22 is supplied todeinterleaving circuits 23. The deinterleaving circuits 23 provide delayamounts which vary with an equal difference, such as 27D, 26D, . . . ,D, and 0, for the 28 symbols so as to cancel the delay amounts providedby the interleaving circuits 13.

[0079] The unit delay amount D of the deinterleaving circuits 23 isequal to four frames in CIRC4, and is equal to seven frames in CIRC7.

[0080] The output data of the deinterleaving circuits 23 is supplied toa C2 decoder 24 for decoding the C2 code. The output (24 symbols) of theC2 decoder 24 is supplied to a two-symbol delay/descrambling circuit 25.The decoded data of 24 symbols is output from the two-symboldelay/descrambling circuit 25.

[0081] An interpolation flag is generated by an interpolation flaggeneration circuit 26 based on error flags from the C1 decoder 22 andthe C2 decoder 24. The interpolation flag is used to interpolate errordata.

[0082] Accordingly, CIRC employs dual error correction coding in boththe vertical C1 sequence and the diagonal C2 sequence. The interleavelengths in CIRC4 and CIRC7 differ from each other.

[0083] In CIRC4, as shown in FIG. 9, the unit delay amount D is equal tofour frames, and the total interleave length is 109 (=108+1) frames,which is slightly greater than one block. In CIRC7, as shown in FIG. 10,the unit delay amount D is equal to seven frames, and the totalinterleave length is 190 (=189+1) frames, which is slightly smaller thantwo blocks.

[0084] The total interleave length defines the correction performancefor burst errors which indicate consecutive bad bits caused byfingerprints on an optical disc, scratches, etc. The greater the totalinterleave length, the higher the correction performance for bursterrors. Since double density CDs require high correction performance forburst errors, it is proposed that CIRC7 error correction coding is usedin the double density CDs to achieve high correction performance forburst errors.

[0085] In the optical disc 1 of the present invention, therefore, thedata encoded with CIRC7 error correction coding is recorded in thesubarea AR2, and the subarea AR2also contains data pattern which can bedecoded with both the CIRC7 and CIRC4 error correction codes. The datawhich can be decoded with both the CIRC7 and CIRC4 error correctioncodes is now described.

[0086] As discussed above, since the interleave lengths in CIRC4 andCIRC7 differ from each other, a CIRC4 decoder is not able to decode dataencoded with CIRC7 error correction coding. Conversely, a CIRC7 decoderis not able to decode data encoded with CIRC4 error correction coding.

[0087] However, data in a particular array can be decoded by both aCIRC4 decoder and a CIRC7 decoder.

[0088]FIG. 11 illustrates a data array supported by both a CIRC4 decoderand a CIRC7 decoder. In the data array shown in FIG. 11, predetermineddata pattern based on the vertical or C1 sequence is repeated in atwo-dimensional array of data. In the example shown in FIG. 11, datapattern of a1, a2, a3, and a4 is repeated in the vertical direction.

[0089] In this data array, the same data type is aligned in eachhorizontal line. Specifically, as shown in FIG. 11, all of the dataaligned in the first horizontal line is a1, all of the data aligned inthe second horizontal line is a2, all of the data aligned in the thirdhorizontal line is a3, and all of the data aligned in the fourthhorizontal line is a4.

[0090] When such a data array is used in both CIRC4 and CIRC7, datapattern similar to that in the C1 sequence is repeated in the C2sequence. In the example shown in FIG. 11, irrespective of the totalinterleave length (i.e., the diagonal angle), the C2 parity is alwayscomposed of data pattern of a1, a2, a3, and a4.

[0091] When data having such a data array is encoded with CIRC7 errorcorrection coding, the data can be decoded by a CIRC4 decoder. When datahaving such a data array is encoded with CIRC4 error correction coding,the data can be decoded by a CIRC7 decoder.

[0092] As discussed above, since the interleave lengths in CIRC4 andCIRC7 differ from each other, normally, data encoded with CIRC7 errorcorrection coding cannot be decoded by a CIRC4 decoder, and data encodedwith CIRC4 error correction coding cannot be decoded by a CIRC7 decoder.However, data which is constructed such that predetermined data patternis repeated in the vertical direction would be supported by both a CIRC7decoder and a CIRC4 decoder.

[0093] According to the optical disc of the present invention,therefore, the characteristics of data supported by both a CIRC7 decoderand a CIRC4 decoder are used to determine whether data recorded in thedisc is original data or copied data. This processing is now described.

[0094]FIG. 12 shows the subarea AR2of the second program area PA2 in theoptical disc 1 shown in FIGS. 1 and 2.

[0095] As discussed above, the subarea AR2contains data encoded withCIRC7 error correction coding, and data pattern which can be decodedwith both the CIRC7 and CIRC4 error correction codes is also containedin the subarea AR2. In FIG. 12, portions BA1, BA2, BA3, and BA4 containdata which can be decoded with both the CIRC7 and CIRC4 error correctioncodes, and the remaining portions contain data encoded with CIRC7 errorcorrection coding. In FIG. 12, “◯” mark indicates that no erroruncorrectable with the CIRC4 error correction code occurs, and “x” markindicates that an error uncorrectable with the CIRC4 error correctioncode occurs. The data which can be decoded with both the CIRC7 and CIRC4error correction codes is such that predetermined data pattern based onthe vertical (C1) sequence is repeated, as shown in FIG. 11.

[0096] As discussed above, the optical disc 1 of the present inventionis provided with the subarea AR2which contains data encoded with CIRC7error correction coding, and the subarea AR2also contains data portionswhich can be decoded with both the CIRC7 and CIRC4 error correctioncodes in predetermined pattern at predetermined position. With thisstructure, it is determined whether the disc is an original disc or acopied disc.

[0097]FIG. 13 schematically shows a disc copy from an original opticaldisc 1A to an optical disc 1B.

[0098] In FIG. 13, the original optical disc 1A is an optical discaccording to the present invention. The subarea AR2of the optical disc1A contains data encoded with CIRC7 error correction coding, and thedata portions BA1, BA2, BA3, etc., which can be decoded with both theCIRC4 and CIRC7 error correction codes are also contained inpredetermined pattern at predetermined position of the area AR2, asshown in FIG. 12.

[0099] When the original optical disc 1A is installed in a playbackapparatus 31, the data in the optical disc 1A is read. Typically, CD-DA,CD-ROM, CD-R, or CD-RW discs employ CIRC4 error correction coding. Theplayback apparatus 31 plays back a CD-DA, CD-ROM, CD-R, or CD-RW disc,and includes a CIRC4 error correction decoding circuit 33 for performingCIRC4 error correction.

[0100] The data in the original optical disc 1A installed in theplayback apparatus 31 is error corrected in the CIRC4 error correctiondecoding circuit 33.

[0101] As shown in FIG. 12, the original optical disc 1A is providedwith the subarea AR2which contains data encoded with CIRC7 errorcorrection coding. When the playback data in the subarea AR2is errorcorrected in the CIRC4 error correction decoding circuit 33, anuncorrectable error occurs in most of the data, except for the dataportions BA1, BA2, BA3, etc. which can be decoded with both the CIRC4and CIRC7 error correction codes.

[0102] The processing for handling an uncorrectable error differs fromone device to another. Typically, an uncorrectable error would be filledwith interpolation data. Alternatively, the playback operation isterminated due to failure at the time when an uncorrectable erroroccurs. Although termination of the playback operation prevents a disccopy of the optical disc 1A, it is assumed herein that an uncorrectableerror is filled with interpolation data.

[0103] The playback data in the optical disc 1A which is played back bythe playback apparatus 31 is transmitted to a recording apparatus 32.Assuming that an uncorrectable error has been filled with interpolationdata by the playback apparatus 31, data output from the playbackapparatus 31 has interpolation data mostly filled in the data recordedin the subarea AR2 is.

[0104] The optical disc 1B is installed in the recording apparatus 32.The recording apparatus 32 includes a CIRC4 encoding circuit 34 forperforming CIRC4 error correction coding.

[0105] The data input to the recording apparatus 32 is supplied to theCIRC4 encoding circuit 34. The input data is encoded with CIRC4 errorcorrection coding in the CIRC4 encoding circuit 34. Thus, the CIRC4error correction coded data is recorded in the optical disc 1B.

[0106] As discussed above, the data output from the playback apparatus31 has interpolation data mostly filled in the data recorded in thesubarea AR2. In the CIRC4 encoding circuit 34, a CIRC4 error correctioncode is applied to the interpolation data.

[0107] As a result, in the copied optical disc 1B, the interpolationdata encoded with CIRC4 error correction coding is recorded in thesubarea AR2, as shown in FIG. 14B. In contrast, as shown in FIG. 14A,the subarea AR2 in the original optical disc 1A contains data encodedwith CIRC7 error correction coding, and the data portions BA1, BA2, BA3,etc. which can be decoded with both the CIRC4 and CIRC7 error correctioncodes are also recorded in predetermined pattern at predeterminedposition of the subarea AR2.

[0108] As is apparent from comparison between the original disc 1A shownin FIG. 14A and the copied disc 1B shown in FIG. 14B, the data containedin the subarea AR2 in the original optical disc 1A which is encoded withCIRC7 error correction coding, and the data includes the data portionsBA1, BA2, BA3, etc. which can be decoded with both the CIRC4 and CIRC7error correction codes in predetermined pattern at predeterminedposition. In the copied optical disc 1B, in contrast, the data containedin the subarea AR2 is error corrected-with the CIRC4 error correctioncode, and the data portions BA1, BA2, BA3, etc. which can be decodedwith both the CIRC4 and CIRC7 error correction codes are not clearlyidentified.

[0109] Therefore, based on whether or not an error occurs in otherportions of the subarea AR2 of the optical disc 1 than the data portionsBA1, BA2, BA3, etc. which can be decoded with both the CIRC4 and CIRC7error correction codes, it can be determined whether or not the opticaldisc 1 is original.

[0110] It is assumed that the playback data in the subarea AR2 of theoptical disc 1 is decoded with the CIRC4 error correction code. Then, inthe original optical disc 1A, the data portions BA1, BA2, BA3, etc.which can be decoded with both the CIRC4 and CIRC7 error correctioncodes are error corrected, and the remaining portions contains anuncorrectable error. In the copied optical disc 1B, however, since thedata recorded in the subarea AR2 is encoded with CIRC4 error correctioncoding, no error occurs in the data.

[0111] There may be a case in which an error occurs in the subareaAR2due to any other different processing or due to disc damage. In thiscase, it is determined that the disc has a problem unless the dataportions BA1, BA2, BA3, etc. which can be decoded with both the CIRC4and CIRC7 error correction codes are detected from the playback data inthe subarea AR2.

[0112] Accordingly, data encoded with CIRC7 error correction coding isrecorded in the subarea AR2, and data portions which can be decoded withboth the CIRC7 and CIRC4 error correction codes are included inpredetermined pattern at predetermined portions of the subarea AR2, thusmaking it possible to determine whether the disc is an original disc ora copied disc based on error corrected data in the subarea AR2.

[0113]FIG. 15 shows the configuration of a recording apparatus forrecording data in the above-noted optical disc 1. In FIG. 15, digitalaudio data to be recorded in the program area PA1 of the optical disc 1shown in FIG. 1 is supplied to an input terminal 51.

[0114] As content data to be recorded in the program area PA2, audiodata which is compressed using, for example, ATRAC3 is supplied to aninput terminal 52.

[0115] Data to be recorded in the subarea AR2is supplied to an inputterminal 55. The data supplied to the input terminal 55 may be playedback only by a dedicated drive; however, the data is not limitedthereto, and any data may be supplied to the input terminal 55.

[0116] A data generation circuit 56 generates data which can be decodedwith both the CIRC4 and CIRC7 error correction codes. The data which canbe decoded with both the CIRC4 and CIRC7 error correction codes is suchthat predetermined data pattern based on the vertical (C1) sequence isrepeated when the data is arranged in a two-dimensional array for errorcorrection.

[0117] When digital audio data is recorded in the program area PA1 ofthe optical disc 1, the audio data is supplied from the input terminal51 to a CIRC4 error correction coding circuit 54.

[0118] When audio data compressed using, for example, ATRAC3 is recordedas content data in the subarea AR1 of the program area PA2 of theoptical disc 1, the compressed audio data is supplied from the inputterminal 52 to an encryption circuit 53. The audio data is thenencrypted in the encryption circuit 53. The output of the encryptioncircuit 53 is supplied to the CIRC4 error correction coding circuit 54.

[0119] The CIRC4 error correction coding circuit 54 encodes data withdual error correction coding in the C1 (vertical) sequence and in the C2(diagonal) sequence. In CIRC4, the unit delay amount D is equal to fourframes, and the maximum delay amount is 27D (=108 frames).

[0120] The data to be recorded in the subarea AR2 is supplied from theinput terminal 55. The data from the input terminal 55 is supplied to acontact 57A of a switch circuit 57. The data generation circuit 56generates data which can be decoded with both the CIRC4 and CIRC7 errorcorrection codes. The output of the data generation circuit 56 issupplied to a contact 57B of the switch circuit 57. The switch circuit57 is switched at a predetermined timing. The output of the switchcircuit 57 is supplied to a CIRC7 error correction coding circuit 58.

[0121] The CIRC7 error correction coding circuit 58 encodes data withdual error correction coding in the C1 (vertical) sequence and in the C2(diagonal) sequence. In CIRC7, the unit delay amount D is equal to sevenframes, and the maximum delay amount is 27D (=189 frames).

[0122] When data is recorded in the subarea AR1 of the program area PA2,the content data encoded with CIRC4 error correction coding is suppliedfrom the CIRC4 error correction coding circuit 54 to a subcode addingcircuit 59.

[0123] When CIRC7 error correction coded data is recorded in the subareaAR2, data encoded with CIRC7 error correction coding is supplied fromthe CIRC7 error correction coding circuit 58 to the subcode addingcircuit 59. The switch circuit 57 is switched at a predetermined timing,so that the data encoded with CIRC7 error correction coding can includedata which can be decoded with both the CIRC 4 and CIRC7 errorcorrection codes in predetermined pattern at predetermined position.

[0124] The subcode adding circuit 59 adds a subcode and a framesynchronization signal to one-frame data. The output of the subcodeadding circuit 59 is supplied to a modulation circuit 60. The data to berecorded is EFM modulated in the modulation circuit 60.

[0125] The optical disc 1 is placed on a turntable (not shown), and isdriven to rotate by a spindle motor 61. Under control of a servo controlcircuit 62, the spindle motor 61 is rotated by a spindle control circuit63 at CLV (constant linear velocity) or CAV (constant angular velocity).

[0126] Based on a focus error signal and a tracking error signal, andbased on an operational instruction from a system controller 68, theservo control circuit 62 generates various servo drive signals such asfocus, tracking, sled, and spindle servo drive signals, and outputsthese signals to a two-axis control circuit 64, a sled control circuit65, and a spindle control circuit 63.

[0127] An optical pickup 66 traces a track concentrically or spirallyformed in the optical disc 1, while focusing a light beam of asemiconductor laser used as a light source onto a signal surface of theoptical disc 1. The optical pickup 66 includes an objective lenssupported by a two-axis mechanism (not shown) in a movable manner inboth the focus direction and the tracking direction for focusing thelaser beam from the semiconductor laser onto the signal surface of theoptical disc 1. The two-axis mechanism is controlled by the two-axiscontrol circuit 64 under control of the servo control circuit 62. Thesled mechanism 67 enables the optical pickup 66 to move in the radialdirection of the optical disc 1. The movement of the sled mechanism 67is controlled by the sled control circuit 65 under control of the servocontrol circuit 62.

[0128] The output data of the modulation circuit 60 is supplied to theoptical pickup 66. A laser beam of which the output waveform ismodulated according to the output data of the modulation circuit 60 isoutput from the optical pickup 66. The laser beam is irradiated onto therecording surface of the optical disc 1, thus allowing information to berecorded in the optical disc 1.

[0129]FIG. 16 shows a playback apparatus. In FIG. 16, an optical disc 1is placed on a turntable, and is driven to rotate by a spindle motor 71.Under control of a servo control circuit 73, the spindle motor 71 isrotated by a spindle control circuit 72 at CLV (constant linearvelocity) or CAV (constant angular velocity).

[0130] Based on a focus error signal and a tracking error signal, andbased on an operational instruction from a system controller 87, theservo control circuit 73 generates various servo drive signals such asfocus, tracking, sled, and spindle servo drive signals, and outputsthese signals to a two-axis control circuit 74, a sled control circuit75, and a spindle control circuit 72. An optical pickup 77 traces atrack concentrically or spirally formed in the optical disc 1, whilefocusing a light beam of a semiconductor laser used as a light sourceonto a signal surface of the optical disc 1. The sled mechanism 78allows the optical pickup 77 to move in the radial direction of theoptical disc 1.

[0131] The output signal of the optical pickup 77 is supplied to ademodulation circuit 80 via an RF amplifier 79. The output signal is EFMdemodulated in the demodulation circuit 80. The output data of thedemodulation circuit 80 is supplied to a subcode extracting circuit 81.The subcode extracting circuit 81 extracts subcode data. The output dataof the subcode extracting circuit 81 is supplied to an error correctiondecoding circuit 82 for performing CIRC4 error correction.

[0132] When CD-DA data in the program area PA1 of the optical disc 1 isplayed back, the optical pickup 77 accesses the program area PA1 so thatthe data recorded in the program area PA1 is played back by the opticalpickup 77. The playback output signal is supplied to the errorcorrection decoding circuit 82 via the RF amplifier 79, the demodulationcircuit 80, and the subcode extracting circuit 81.

[0133] The playback signal is CIRC4 error corrected in the errorcorrection decoding circuit 82 to output audio data from the errorcorrection decoding circuit 82. The audio data is then output from anoutput terminal 84.

[0134] When content data in the program area PA2 of the optical disc 1is played back, the optical pickup 77 accesses the program area PA2 sothat the data recorded in the program area PA2 is played back by theoptical pickup 77. The playback output signal is supplied to the errorcorrection decoding circuit 82 via the RF amplifier 79, the demodulationcircuit 80, and the subcode extracting circuit 81.

[0135] The playback signal is CIRC4 error corrected in the errorcorrection decoding circuit 82 to output from the error correctiondecoding circuit 82 audio data which is compressed using, for example,ATRAC3, as described above, and which is encrypted. The output data ofthe error correction decoding circuit 82 is supplied to a decryptioncircuit 83, and is decrypted in the decryption circuit 83. The outputdata of the decryption circuit 83 is output from an output terminal 85.

[0136] The subarea AR2 of the optical disc 1 contains data encoded withCIRC7 error correction coding, and the data includes data portions whichcan be decoded with both the CIRC4 and CIRC7 error correction codes inpredetermined pattern at a predetermined position.

[0137] When it is determined whether the optical disc 1 is an originaldisc or a copied disc, the optical pickup 77 accesses the subarea AR2 ofthe optical disc 1, and the playback data of the subarea AR2 is suppliedto the error correction decoding circuit 82. The playback data of thesubarea AR2 is CIRC4 error corrected in the error correction decodingcircuit 82, and the error-corrected data is supplied to a determinationcircuit 86.

[0138] The determination circuit 86 checks uncorrectable error pattern.The output of the determination circuit 86 is passed to the systemcontroller 87, and it is determined in the system controller 87 whetherthe optical disc 1 is an original disc or a copied disc. The result ofdetermination is displayed on a display 88.

[0139]FIG. 17 is a flowchart showing a process for determining whetherthe optical disc 1 is an original disc or a copied disc.

[0140] In FIG. 17, data at predetermined position of the optical disc 1,that is, data recorded in the subarea AR2 is read (step S1). The readdata is subjected to error correction, and it is determined whether ornot the resulting data can contain an uncorrectable error (step S2).

[0141] If it is determined in step S2 that the read data which issubjected to error correction can an uncorrectable error, it isdetermined whether or not an error uncorrectable with a CIRC4 errorcorrection code occurs (step S3).

[0142] If it is determined in step S2 that the read data which issubjected to error correction can contain an uncorrectable error, and ifit is determined in step S3 that an error uncorrectable with the CIRC4error correction code occurs, it is determined whether or not there isany other portion to be checked (step S4). If any other portion to bechecked still remains, the process returns to step S1.

[0143] If it is determined in step S2 that the read data which issubjected to error correction can contain an uncorrectable error, and ifit is determined in step S3 that an error uncorrectable with the CIRC4error correction code does not occur, it is determined that the opticaldisc 1 is not an original disc (step S5).

[0144] If it is determined in step S2 that the read data which issubjected to error correction cannot contain an uncorrectable error,that is, the read data can be decoded with both the CIRC4 and CIRC7error correction codes, it is determined whether or not the CIRC4 errorcorrected data contains an uncorrectable error (step S6).

[0145] If it is determined in step S2 that the read data which issubjected to error correction cannot contain an uncorrectable error, andif it is determined in step S6 that an error uncorrectable with theCIRC4 error correction code does not occur, it is determined whether ornot there is any other portion to be checked (step S4). If any otherportion to be checked still remains, the process returns to step S1.

[0146] If it is determined in step S2 that the read data which issubjected to error correction cannot contain an uncorrectable error, andif it is determined in step S6 that an error uncorrectable with theCIRC4 error correction code occurs, it is determined whether or not theuncorrectable error can be caused by scratches or the like (step S7). Ifthe uncorrectable error cannot be caused by scratches or the like, it isdetermined that the optical disc 1 is not an original disc (step S5).For example, if several hundred bytes of consecutive errors occur, itcan be determined that the errors are caused by scratches or the like.If it is determined in step S7 that the uncorrectable error can becaused by scratches or the like, it is determined in step S4 whether ornot there is any other portion to be checked.

[0147] If it is determined in step S4 that any other portion to bechecked still remains, the process returns to step S1 to repeat theprocessing discussed above. If it is determined in step S4 that all theportions to be checked have been completely processed, it is determinedthat the optical disc 1 is an original disc (step S8). As a result, theplayback operation of the optical disc 1 starts.

[0148] If it is determined that the optical disc 1 is not an originaldisc, this result may be displayed on the display 88 as an example. Ifthe optical disc 1 is not an original disc, it may be suitable toprohibit a playback of the optical disc 1 installed in the playbackapparatus. If the optical disc 1 is not an original disc, it may also besuitable to eject the optical disc 1 from the playback apparatus.

[0149] As discussed above, in an optical disc according to the presentinvention, the subarea AR2 contains data encoded with CIRC7 errorcorrection coding, and the subarea AR2 also contains data portions whichcan be decoded with both the CIRC4 and CIRC7 error correction codes inpredetermined pattern at predetermined position. With the structure ofthe optical disc, it can be determined whether or not the optical discis original by comparing a result of CIRC4 error correction decodingwith locations in which an error occurs and does not occur when the discis an original disc.

[0150] In the foregoing description, the optical disc 1 shown in FIGS. 1and 2 is a two-session disc which is divided into an inner circumferencearea and an outer circumference area, and one of the inner and outercircumference areas contains CD-DA data and the other containscompressed and encoded audio data. However, it is anticipated that aone-session optical disc shown in FIG. 18 may also be used.

[0151] The optical disc shown in FIG. 18 is formed of a lead-in area LIat the innermost circumference thereof, a program area PA surroundingthe lead-in area LI, and a lead-out area LO surrounding the program areaPA. The program area PA is divided into subareas AR11 and AR12. Thesubarea AR11contains data encoded with CIRC4 error correction coding,and the subarea AR12 contains data encoded with CIRC7 error correctioncoding. The data recorded in the subarea AR12 includes data patternwhich can be decoded with both the CIRC4 and CIRC7 error correctioncodes. With the structure of this type of disc, it can be determinedfrom error pattern of the subarea AR12 whether the disc is an originaldisc or a copied disc.

[0152] In the foregoing description, the present invention has beendiscussed in the context of data which can be decoded with both theCIRC4 and CIRC7 error correction codes. However, CIRC encoded datahaving any interleave length can be decoded as far as the data isarranged so that predetermined data pattern based on the vertical (C1)sequence is repeated.

[0153] The data which can be decoded with a plurality of errorcorrection coding schemes is not limited to CIRC encoded data, and maybe further extended to data encoded with any other error correctioncoding applied in two sequences. Similarly to data encoded with CIRCcoding, for example, data encoded with product coding applied in boththe vertical direction and the horizontal direction can also be decodedwith a plurality of coding schemes.

[0154] In the foregoing description, data encoded with CIRC7 errorcorrection coding is recorded in the subarea AR2 of an optical disc, andthe subarea AR2 also contains data pattern which can be decoded withboth the CIRC7 and CIRC4 error correction codes, thereby determiningwhether the disc is an original disc or a copied disc. However, thispattern may be used to represent information.

[0155] For example, unique ID information may be added to a disc. Theunique ID information added to a disc may be effective to manageproduction information or shipping state of that disc. The IDinformation may also be used to manage version updates. The IDinformation unique to each disc may be added, or the ID informationunique to playback-only discs which are manufactured using a singlestamper may be added.

[0156] When unique ID information is added to discs, it is essential toavoid the ID information of the discs from being copied.

[0157] Accordingly, data pattern which can be decoded with both theCIRC4 and CIRC7 error correction codes and which is included in CIRC7encoded data recorded in the subarea AR2 may be used to represent the IDinformation of discs.

[0158] Specifically, in the subarea AR2, as shown in FIG. 12, the dataportions BA1, BA2, BA3, etc., can be decoded with both the CIRC4 andCIRC7 error correction code, and the remaining data portions are encodedwith CIRC7 error correction coding. When the data recorded in thesubarea AR2 is CIRC4 error corrected during the playback process, nouncorrectable error occurs in the data portions BA1, BA2, BA3, etc.,while an uncorrectable error occurs in the remaining data portions, asshown in FIG. 12.

[0159] When certain information is represented using data pattern whichcan be decoded with both the CIRC7 and CIRC4 error correction codes andwhich is contained in CIRC7 encoded data recorded in the subarea AR2,for example, as in FIG. 19, a combination of information “1” whichindicates the data portions BA1, BA2, BA3, etc., in which no erroruncorrectable with CIRC4 coding occurs, and information “0” whichindicates the remaining portions in which an error uncorrectable withCIRC 4 coding occurs is used. Of course, a portion in which no erroruncorrectable with CIRC4 coding occurs may be indicated by information“0” and a portion in which an error uncorrectable with CIRC4 codingoccurs may be indicated by information “1”. A combination of information“1” and information “0” is used to represent certain information.

[0160] When data is CIRC error corrected during the playback process,the data portions BA1, BA2, BA3, etc., are designated by information “1”and the remaining portions are designated by information “0”. Then, theinformation can be decoded.

[0161] As discussed above, data pattern which can be decoded with boththe CIRC7 and CIRC4 error correction codes may be corrupted if copied.Thus, the information represented using the data pattern which can bedecoded with both the CIRC7 and CIRC4 error correction codes is suitablefor, for example, identifying the disc.

[0162] It is understood that the information represented using the datapattern which can be decoded with both the CIRC7 and CIRC4 errorcorrection codes is not limited to ID information of discs. Such datapattern is suitable, in particular, for recording information whichindicates “copy never”.

[0163] In the foregoing description, the CIRC7 encoded data in thesubarea AR2 includes data pattern which can be decoded with both theCIRC7 and CIRC4 error correction codes, which is used to representcertain information, and no error uncorrectable with CIRC4 coding occursin a portion in which this data pattern is recorded. With use of thedata pattern which can be decoded with both the CIRC7 and CIRC4 errorcorrection codes, as discussed above, a portion in which no erroruncorrectable with CIRC4 coding occurs can be easily formed in the CIRC7encoded data.

[0164] Instead of data which can be decoded with both the CIRC7 andCIRC4 error correction codes, data encoded with CIRC7 error correctioncoding and data encoded with CIRC4 error correction coding may berecorded in predetermined pattern, which are used to represent certaininformation.

[0165] The illustrated embodiment has been described in the context ofexample in which original content data is recorded in a disc and thisdisc is copied. However, the present invention is not limited to thisexample, and may be applied to the case in which original content datais delivered over a computer network.

[0166] Specifically, music data downloaded over a network is encodedwith CIRC4 error correction coding, and the encoded data includes errorpattern uncorrectable with CIRC4 coding. The error pattern uncorrectablewith CIRC4 coding may be implemented by providing an area containingCIRC7 encoded data, and by inserting data portions which can be decodedwith both the CIRC4 and CIRC7 error correction codes into the CIRC7encoded data in predetermined pattern, as discussed above. It isanticipated that this pattern may be used to represent certaininformation, as discussed above. In this case, the downloaded contentdata contains error pattern uncorrectable with CIRC4 coding, and theerror pattern uncorrectable with CIRC4 coding is corrupted when the datais copied. As a result, it can be determined whether or not the receivedmusic data is original data.

[0167] In the above-described optical disc 1, the subarea AR2 containsdata encoded with CIRC7 error correction coding, and the CIRC7 encodeddata includes a data portion which can be decoded with both the CIRC4and CIRC7 error correction codes. When this data portion is played backas a sound without intention, noise may be caused. Therefore, it isconceivable that a PCM (pulse code modulated) signal in which the upperbits are set to “0” or “1” be embedded in this data portion to reducenoise.

[0168] If a sound reproduced from this data portion is a DC sound or ahigh-frequency sound, users are insensitive to the sound, and may turnup the volume. Accordingly, data “0” and data “1” may be embedded inspecific pattern to reproduce an audible-range sound. As an example, “0”and “1” are repeated every 7.35 kHz.

[0169] Some CIRC decoding circuits do not perform C2 error correctionuntil an error of the C1sequence occurs. For supporting a drive orplayer having such a decoding circuit, it is conceivable that a dataportion which is recorded in the subarea AR2 of a disc and which can bedecoded with both the CIRC4 and CIRC7 error correction codes contain anerror of the C1 sequence.

What is claimed is:
 1. A recording medium including an area in whichdata encoded with a first error correction code is recorded, whereinerroneous uncorrectable data which contains an uncorrectable error whichcannot be corrected with the first error correction code, and erroneouscorrectable data which does not contain an uncorrectable error whichcannot be corrected with the first error correction code are recorded inpredetermined pattern in the recording medium.
 2. A recording mediumaccording to claim 1, wherein the erroneous uncorrectable data is dataencoded with a second error correction code different from the firsterror correction code.
 3. A recording medium according to claim 2,wherein the erroneous correctable data can be decoded with both thefirst error correction code and the second error correction code.
 4. Arecording medium according to claim 3, wherein each of the first errorcorrection code and the second error correction code is applied in atleast two-direction code sequences, the first error correction code andthe second error correction code being different only in view of thecode sequences; and the erroneous correctable data is constructed sothat predetermined data pattern based on one of the two-direction codesequences is repeated.
 5. A recording medium according to claim 3,wherein each of the first error correction code and the second errorcorrection code is applied in a vertical C1 sequence and a diagonal C2sequence, the first error correction code and the second errorcorrection code having different interleave lengths; and the erroneouscorrectable data is constructed so that predetermined data pattern basedon the Cl sequence is repeated.
 6. A recording medium according to claim5, wherein the erroneous correctable data includes an error of the C1sequence.
 7. A recording medium according to claim 1, wherein, in a dataportion in which the erroneous uncorrectable data and the erroneouscorrectable data are recorded in the predetermined pattern, upper bitsare set to the same value.
 8. A recording medium according to claim 1,wherein a data portion in which the erroneous uncorrectable data and theerroneous correctable data are recorded in the predetermined pattern isplayed back as an audible-range sound.
 9. A recording medium accordingto claim 8, wherein, in the data portion in which the erroneousuncorrectable data and the erroneous correctable data are recorded inthe predetermined pattern, data “zero” and data “one” are repeated in apredetermined period.
 10. A recording medium according to claim 1,wherein a data portion in which the erroneous uncorrectable data and theerroneous correctable data are recorded in the predetermined pattern isused to identify the recording medium.
 11. A recording medium accordingto claim 1, wherein a data portion in which the erroneous uncorrectabledata and the erroneous correctable data are recorded in thepredetermined pattern is used to determine whether or not the recordingmedium is original.
 12. A recording method comprising the steps of:recording data encoded with a first error correction code in a recordingarea of a recording medium; and recording erroneous uncorrectable datawhich contains an uncorrectable error which cannot be corrected with thefirst error correction code and erroneous correctable data which doesnot contain an uncorrectable error which cannot be corrected with thefirst error correction code in predetermined pattern at predeterminedposition of the recording medium.
 13. A recording method according toclaim 12, wherein the first erroneous uncorrectable data is data encodedwith a second error correction code different from the first errorcorrection code.
 14. A recording method according to claim 13, whereinthe erroneous correctable data can be decoded with both the first errorcorrection code and the second error correction code.
 15. A recordingmethod according to claim 14, wherein each of the error correction codeand the second error correction code is applied in at leasttwo-direction code sequences, the first error correction code and thesecond error correction code being different only in view of the codesequences; and the erroneous correctable data is constructed so thatpredetermined data pattern based on one of the two-direction codesequences is repeated.
 16. A recording method according to claim 14,wherein each of the first error correction code and the second errorcorrection code is applied in a vertical Cl sequence and a diagonal C2sequence, the first error correction code and the second errorcorrection code having different interleave lengths; and the erroneouscorrectable data is constructed so that predetermined data pattern basedon the C1 sequence is repeated.
 17. A recording method according toclaim 16, wherein the erroneous correctable data includes an error ofthe C1 sequence.
 18. A recording method according to claim 12, wherein,in a data portion in which the erroneous uncorrectable data and theerroneous correctable data are recorded in the predetermined pattern,upper bits are set to the same value.
 19. A recording method accordingto claim 12, wherein data which is played back as an audible-range soundis recorded so that the erroneous uncorrectable data and the erroneouscorrectable data are recorded in the predetermined pattern.
 20. Arecording method according to claim 19, wherein data “zero” and data“one” which are repeated in a predetermined period are recorded so thatthe erroneous uncorrectable data and the erroneous correctable data arerecorded in the predetermined pattern.
 21. A recording apparatus of arecording medium, comprising: a recording unit for recording data in therecording medium; an error correction coding unit for encoding inputdata with a first error correction code; a modulation unit formodulating the output data of the error correction coding unit to outputthe modulated data to the recording unit; and a data generation unit forgenerating data which can be decoded with both the first errorcorrection code and a second error correction code different from thefirst error correction code, and for supplying the generated data to theerror correction coding unit.
 22. A recording apparatus according toclaim 21, wherein data based on the output data of the error correctioncoding unit obtained by encoding the input data supplied to the errorcorrection coding unit, and data based on the output data of the errorcorrection coding unit obtained by encoding the data supplied from thedata generation unit to the error correction coding unit are recorded inpredetermined pattern in the recording medium.
 23. A recording apparatusaccording to claim 21, wherein each of the first error correction codeand the second error correction code is applied in at leasttwo-direction code sequences, and the first error correction code andthe second error correction code are different only in view of the codesequences.
 24. A recording apparatus according to claim 21, wherein eachof the first error correction code and the second error correction codeis applied in a vertical C1 sequence and a diagonal C2 sequence, and thefirst error correction code and the second error correction code havedifferent interleave lengths.
 25. A playback apparatus of a recordingmedium, comprising: a head for reading data recorded in the recordingmedium; a demodulation unit for demodulating the output signal of thehead; an error correction unit for performing error correction on theoutput data of the demodulation unit using an error correction code; anda determination unit for determining the recording medium based onwhether or not the result of the error correction performed by the errorcorrection unit is a predetermined result.
 26. A playback apparatusaccording to claim 25, wherein the determination unit determines therecording medium based on whether or not error pattern uncorrectablewith the error correction code as a result of the error correctionperformed by the error correction unit is predetermined pattern.
 27. Aplayback apparatus according to claim 26, wherein the determination unitdetermines that the recording medium is an original recording mediumwhen the uncorrectable error pattern is the predetermined pattern.
 28. Aplayback apparatus according to claim 26, wherein the determination unitdetermines that the recording medium is not an original recording mediumwhen the uncorrectable error pattern is not the predetermined pattern,and the playback apparatus terminates a playback of the recordingmedium.
 29. A playback apparatus according to claim 25, wherein datawhich contains an error uncorrectable with the error correction code,and data which does not contain an error uncorrectable with the errorcorrection code are recorded in predetermined pattern at predeterminedposition of the recording medium; and the determination unit determinesthe recording medium based on whether or not the data read from thepredetermined position of the recording medium by the head is dataobtained as a result of the error correction performed by the errorcorrection unit.
 30. A playback apparatus according to claim 29, whereinthe determination unit determines whether or not the recording medium isan original recording medium based on whether or not the result of theerror correction performed by the error correction unit is thepredetermined result.
 31. A playback method of a recording medium,comprising the steps of: reading data recorded in the recording medium;demodulating the read data; performing error correction on thedemodulated data with an error correction code; and determining therecording medium based on whether or not the result of the errorcorrection is a predetermined result.
 32. A playback method according toclaim 31, wherein the recording medium is determined based on whether ornot error pattern uncorrectable with the error correction code as aresult of the error correction is predetermined pattern.
 33. A playbackmethod according to claim 32, wherein it is determined that therecording medium is an original recording medium when the uncorrectableerror pattern is the predetermined pattern.
 34. A playback methodaccording to claim 33, wherein, when it is determined that the recordingmedium is an original recording medium, a playback of the recordingmedium starts.
 35. A playback method according to claim 32, wherein itis determined that the recording medium is not an original recordingmedium when the uncorrectable error pattern is not the predeterminedpattern, and a playback of the recording medium terminates.
 36. Aplayback method according to claim 31, wherein data which contains anerror uncorrectable with the error correction code, and data which doesnot contain an error uncorrectable with the error correction code arerecorded in predetermined pattern at predetermined position of in therecording medium; and the recording medium is determined based onwhether or not the data read from the predetermined position of therecording medium is data obtained as a result of the error correction.37. A playback method according to claim 36, wherein it is determinedwhether or not the recording medium is an original recording mediumbased on whether or not the result of the error correction is thepredetermined result.
 38. A data determination method comprising thesteps of: performing error correction on transmitted data using an errorcorrection code; and determining whether or not the transmitted data isoriginal data based on whether or not the result of the error correctionis a predetermined result.
 39. A data determination method according toclaim 38, wherein it is determined whether or not the transmitted datais original data based on whether or not error pattern uncorrectablewith the error correction code is predetermined pattern.
 40. A datadetermination method according to claim 39, wherein it is determinedthat the transmitted data is original data when the uncorrectable errorpattern is the predetermined pattern.
 41. A data determination methodaccording to claim 39, wherein it is determined that the transmitteddata is not original data when the uncorrectable error pattern is notthe predetermined pattern.